JP4717316B2 - Component built-in wiring board, method of manufacturing component built-in wiring board - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a component built-in wiring board and a manufacturing method thereof, and more particularly, to a component built-in wiring board suitable for further improving component mounting density and a manufacturing method thereof.
[0002]
[Prior art]
In recent years, electronic technology has advanced, electronic devices and communication devices have become highly functional, and miniaturization has also progressed. In such a situation, for example, semiconductor mounting on a wiring board, a bare chip mounting method not using package mounting has been put into practical use in order to improve mounting density. In addition, passive components such as capacitors and resistors are downsized to a size of 0.6 mm × 0.3 mm (0603).
[0003]
As the wiring board itself, the electrical connection between the wiring layers (interlayer connection) is based on the conductive layer formed on the inner surface of the through hole, so that the CO ₂ There is a shift to one in which blind vias are formed for each layer by laser or UV-YAG laser and plating is formed on the inner surface thereof, or in which conductive paste is filled. In addition, for forming a wiring pattern, a method (additive method) of forming a metallized wiring by plating instead of a method using etching (subtractive method) is being used for miniaturization. Thereby, it is possible to form finely up to about L / S (line / space) = about 20 μm / 20 μm.
[0004]
In such a situation, in order to further improve the component mounting density and contribute to downsizing of the device, for example, a component built-in wiring board in which components are built in the wiring board can be used. An example of the component built-in wiring board is disclosed in Japanese Utility Model Laid-Open No. 5-53269.
[0005]
[Patent Document 1]
Japanese Utility Model Publication No. 5-53269
[0006]
[Problems to be solved by the invention]
In what is disclosed in the above publication, the component mounted and mounted in the substrate is the land (corresponding to the thickness direction of the plate) provided corresponding to each terminal of the component, as in the case of mounting on the substrate. Are formed in the vertical direction). Here, when the component is built in the substrate, it is preferable that the periphery of the component is covered and intimately covered with an insulating resin except for the electrical connection portion. This is because reliability is deteriorated when an unfilled portion is formed. In this regard, in the above-mentioned publication, when a gap is generated between the component and the substrate on which the component is directly mounted, the gap is very narrow and the resin is not easily filled.
[0007]
The present invention has been made in consideration of the above-described circumstances, and in the component built-in wiring board and the manufacturing method thereof, the component built-in wiring board capable of further improving the component mounting density without impairing the reliability and the manufacturing thereof It aims to provide a method.
[0008]
[Means for Solving the Problems]
In order to solve the above problems, the component built-in wiring board according to the present invention is: First of first radius arc A second arc of a second radius larger than the first radius that is continuous with the first arc, a third arc of substantially the first radius that is continuous with the second arc, and the third arc And a fourth arc of the second radius substantially continuous with the first arc. A first insulating layer having an opening having an edge, and the opening Above Edge The first arc and the third arc On the inner wall of the arc Respectively In addition, Inside the component built-in wiring board Formed substantially perpendicular to the direction, and Of the component built-in wiring board It is buried in the upper and lower surfaces without being exposed. 1st, 2nd A conductive layer; 1st, 2nd Having a terminal and embedded 1st, 2nd Conductive layer Respectively To the above 1st, 2nd Make sure the terminals are facing each other Of the component built-in wiring board In the board In The embedded electric / electronic component having a shape substantially symmetrical with respect to the thickness direction, and the embedded electric / electronic component 1st, 2nd Terminal and said 1st, 2nd Provided in the gap with the conductive layer 1st, 2nd Terminal and said 1st, 2nd With conductive layer Respectively Connect electrically and mechanically 1st, 2nd Of the outer surface of the solder and the embedded electrical / electronic component, the solder 1st, 2nd It is provided so as to cover the portion other than the portion connected to the solder and to adhere substantially symmetrically in the vertical direction of the plate thickness of the electric / electronic component, and 1st, 2nd Conductive layer Of the component built-in wiring board In the board In To bury it 1st, 2nd The upper and lower end surfaces of the conductive layer are sandwiched from above and below, and two upper and lower second and third insulating layers are provided.
[0009]
In this component built-in wiring board, a conductive layer for connecting to the terminal of the built-in component is formed in the plate thickness direction. Therefore, the connection between the terminal of the component and the conductive layer is made by, for example, a conductive member bridged in the horizontal direction. Therefore, the gap is less likely to occur around the built-in component, and the upper and lower insulating layers are in close contact with the built-in component. Therefore, no gap is generated around the built-in component, and reliability is not deteriorated.
[0010]
The component built-in wiring board manufacturing method according to the present invention includes a step of manufacturing a core wiring board having first conductive layers on at least upper and lower surfaces, and the manufactured core wiring board with respect to an in-plane direction. Almost vertical And almost circular Forming two through holes adjacent to each other, forming a second conductive layer on the inner wall surface of the two through holes formed, and patterning the first conductive layer The two through holes are formed as a single through hole having four arcs. And the second conductive layer formed on the inner wall surface of the two through holes is divided into third and fourth conductive layers. As described above, the core wiring board on which the second conductive layer is formed is positioned at the position of the core wiring board that is orthogonal to the direction in which the two through holes are arranged. A radius larger than the radius of each of the two through holes. A process of drilling at two locations, and the drilling The third and fourth layers formed by dividing the second conductive layer by For each conductive layer 1st, 2nd A step of positioning an electric / electronic component having a substantially plane-symmetrical shape in the thickness direction in the single through-hole so that each of the terminals faces each other, and the positioning of the positioned electric / electronic component The first and second And the terminal 3rd, 4th Each of the conductive layers is connected to each other by solder, and the upper and lower end surfaces of the divided conductive layer are sandwiched from above and below by overlapping each of the upper and lower surfaces of the core wiring board to which the electrical / electronic components are connected by the solder, and And a step of laminating and forming an insulating layer so as to fill the periphery of the electric / electronic component almost symmetrically in the plate thickness direction.
[0011]
In this manufacturing method, a conductive layer for connecting to a terminal of a built-in component is formed in a through hole provided in the core wiring board. The conductive layer formed in the through hole is divided in accordance with the number of terminals of the built-in component, and the core wiring board is processed so that a space in which the electric / electronic component to be built is to be created is created. Therefore, the connection between the terminal of the component and the conductive layer can be made, for example, by a conductive member having a bridge shape in the horizontal direction. Therefore, the gap is less likely to occur around the built-in component, and an insulating layer for stacking can be filled and adhered around the built-in component. Therefore, it is possible to manufacture a wiring board in which no gap is generated around the built-in component and reliability is not deteriorated.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
As an embodiment of the present invention, the electric / electronic component is The Capacitor, chip resistor, or chip inductor. These are representative of electric / electronic components. In addition, discrete semiconductor devices (Da Iode etc.) can be used.
[0013]
As an embodiment, the conductive layer further includes a wiring layer that can be electrically connected in the lateral direction, and the number thereof is four. As described above, the conductive layer is embedded in the upper and lower surfaces of the plate without being exposed, but four wiring layers are provided in the lateral direction of the embedded position. When there are four wiring layers, the thickness of the portion can be easily set to, for example, about 0.2 mm to 0.6 mm by selecting the thickness of each insulating layer (for example, resin layer) located between the wiring layers. Can be. Such a dimension is equal to or slightly larger than the thickness of an electrical component such as a chip resistor, and therefore a space for incorporating the component can be easily secured.
[0014]
As an embodiment, the wiring layers are electrically connected to each other by conductive bumps. Suitable for higher-density mounting due to interlayer connection using conductive bumps.
[0015]
As an embodiment, the conductive bumps are positioned so as to overlap with the wiring layer. Since the conductive bumps are positioned so as to overlap the wiring layer, it is suitable for higher density mounting.
[0016]
As an embodiment, the upper and lower two 2nd, 3rd Two inner wiring layers provided in contact with the inner side surfaces of the insulating layer; 2nd, 3rd Two outer wiring layers provided in contact with the outer surfaces of the insulating layer, and the two upper and lower layers. 2nd, 3rd Electrical conduction between the inner wiring layer and the outer wiring layer sandwiching each insulating layer is made by conductive bumps. Interlayer connection between the inner wiring layer and the outer wiring layer is made by conductive bumps, which is suitable for higher density mounting.
[0018]
Moreover, as an embodiment in the production method of the present invention, at least on both the upper and lower surfaces First The step of manufacturing a core wiring board having a conductive layer is a process of manufacturing a core wiring board having four wiring layers, and electrical connection between these wiring layers is made by conductive bumps. Manufactured. By using four wiring layers, the thickness of the wiring layers is set to a dimension that facilitates securing the component built-in space, and a higher density mounting is realized by performing interlayer connection between the wiring layers with conductive bumps.
[0019]
Also, as an embodiment, the formed Two Inside of the through hole Second on the wall The step of forming a conductive layer includes a step of forming a conductive layer as a base by electroless plating and a step of forming a conductive layer as an upper layer by electrolytic plating using the formed base as a seed. Efficient plating can be formed by using such two-stage plating.
[0021]
Further, as an embodiment, the drilling Formed by the third, fourth For each conductive layer The first and second In the single through-hole, the step of positioning the electric / electronic component having a substantially plane-symmetric shape in the thickness direction in the single through-hole faces the core wiring except for the single through-hole. A support member is applied to the lower position of the plate, and the electric / electronic component is positioned on the support member. The mounting position of the component is a space formed in the core wiring board. By using the support member in this way, it is possible to use an existing manufacturing apparatus such as a normal mounter.
[0023]
Based on the above, embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a cross-sectional view (FIG. 1 (a)) and a partial plan view (FIG. 1 (b)) showing a schematic configuration of a component built-in wiring board according to an embodiment of the present invention.
[0024]
As shown in FIG. 1A, this embodiment is a six-layer wiring board having insulating layers 11 to 15 and having wiring layers 21 to 26 in the vicinity of the boundary and on the upper and lower surfaces, respectively. Electrical connections (interlayer connections) between adjacent wiring layers are made by conductive bumps 41 to 45, and these conductive bumps 41 to 45 can be arranged in a superimposed manner. Such conductive bumps 41 to 45 improve the utilization efficiency of the main surface of the wiring board and are suitable for high-density mounting. Reference numerals 31 and 32 on the upper and lower surfaces are solder resists.
[0025]
In addition, an electric / electronic component 33 (for example, a chip resistor here) is incorporated so as to be included in the horizontal level of the inner wiring layers 22, 23, 24, 25. Both terminals of the component 33 face the conductive layers 34 and 35 formed in the plate thickness direction and are electrically and mechanically connected via solders 36 and 37 as connecting members. As shown in the drawing, the conductive layers 34 and 35 can be directly connected to the inner wiring layers 22, 23, 24, and 25.
[0026]
The component 33 is arranged as shown in FIG. That is, a through space is formed in the inner insulating layers 12, 13, and 14 in order to incorporate the component 33, and this through space is formed by connecting the component 33 and the solders 36 and 37 for connection and the insulating layers 11 and 15 on both the upper and lower sides. It is occupied by the protruding part to the inside. Note that the part 33 is usually smaller in thickness than the width shown in FIG. 1B although the thickness shown in FIG. 1A is smaller than the width shown in FIG. The thickness of 33 is also displayed larger.
[0027]
Specifically, when a chip resistor of 0603 is used as the component 33, these insulating layers 12, 13 are set so that the total thickness of the insulating layers 12, 13, 14 is, for example, about 0.2 mm to 0.3 mm. 14 each have a thickness of about 0.06 mm to 0.1 mm.
[0028]
In addition, each part material is, for example, epoxy resin, polyimide resin, bismaleimide triazine resin or the like for the insulating layers 11 to 15, and copper or the like for the wiring layers 21 to 26 or the conductive layers 34 and 35, for example, to the conductive bumps 41 to 45. For example, a conductive resin in which fine metal particles (silver, copper, gold, solder, etc.) are dispersed in the resin can be used. For the solders 36 and 37, a conductive resin can be used instead.
[0029]
The wiring board having the structure of this embodiment is extremely preferable for improving the reliability because the insulating layers 11 and 15 are in close contact with each other so as to cover the built-in component 33 and prevent the generation of voids. In the above description, the chip resistor has been described as an example of the electric / electronic component 33. However, the same application is possible when the terminal arrangement structure such as a chip capacitor, chip inductor, and chip diode is almost the same as the chip resistor. is there.
[0030]
Even in the case of chip-type discrete transistors and semiconductor devices housed in packages, for example, if the lead pins protrude horizontally from the middle of the thickness direction of the mold resin that is the package, the number of lead pins in the board thickness direction It is possible to cope with this by separately forming the conductive layer. In the case of a bare semiconductor chip, by forming a protruding electrode on a pad as close as possible to the periphery, this protruding electrode can be used for electrical and mechanical connection with a conductive layer on the wiring board side. .
[0031]
Next, an example of a process for manufacturing the component built-in wiring board having the above structure will be described with reference to FIGS. 2 to 6 are diagrams schematically showing a process of manufacturing the component built-in wiring board according to the embodiment of the present invention in a cross section (or a partial plane). In these drawings, the same reference numerals are assigned to the same equivalent portions. Moreover, the same code | symbol is attached | subjected also to the site | part corresponding to the wiring board shown in FIG.
[0032]
FIG. 2 is a cross-sectional view showing a manufacturing process of a core wiring board (a wiring board material including a layer in which components are to be incorporated) of the wiring boards. First, as shown in FIG. 2A, a copper foil (thickness is, for example, 18 μm) 22a is prepared, and a substantially conical shape is formed at a required position (position according to a specific wiring board layout) on the copper foil 22a. Conductive bumps 42a are formed. This can be done, for example, by printing a conductive paste on the copper foil 22a using screen printing.
[0033]
As the screen plate in this case, for example, a screen plate having 0.2 mm through holes (pits) can be used. Thereby, for example, a conductive bump having a bottom diameter of about 0.15 mm or more can be formed. As the conductive paste, for example, a paste in which metal particles (silver, gold, copper, solder, etc.) are dispersed in a paste-like resin such as an epoxy resin, and a volatile solvent is mixed can be used. After printing, the conductive paste is cured by drying in an oven, for example.
[0034]
Next, using a dedicated machine, the conductive bumps 42a are semi-cured as shown in FIG. 2 (b) with the copper foil 22a facing the prepreg (thickness is, for example, 0.06 mm) to be the insulating layer 12. It penetrates the prepreg in the state. For example, the prepreg is obtained by impregnating a reinforcing material such as glass fiber with a curable resin such as an epoxy resin. Moreover, it is in a semi-cured state before curing, and has thermoplasticity (fluidity due to heat) and thermosetting. In addition, the thing of the state shown in FIG.2 (b) is referred later by the wiring board raw material 1 or 1a or 1b (the thing which has the same structure is 1a or 1b).
[0035]
Next, as shown in FIG.2 (c), copper foil (thickness is 18 micrometers) 23a is laminated | stacked and integrated, and a prepreg is hardened. For this purpose, a vacuum laminating hot press is used to set it to a predetermined temperature and pressure profile. At the time of lamination and integration, the conductive bump 42a is crushed and plastically deformed (= becomes conductive bump 42), and electrical connection with the copper foil 23a is established.
[0036]
Next, as shown in FIG. 2D, the wiring layer 23 is formed by patterning the copper foil 23a on one side. For this purpose, for example, the surface of the copper foil 23a is first chemically polished to improve the adhesion with the resist dry film, and then the resist dry film is laminated on the copper foil 23a. Then, the dry film is exposed with an alignment exposure machine having, for example, an ultrahigh pressure mercury lamp through a photomask, and further spray-developed with sodium carbonate. By leaving the dry film of this development pattern on the copper foil 23a, a patterned resist is formed on the copper foil 23a.
[0037]
When the resist is formed on the copper foil 23a, a chemical solution based on ferric chloride is used as an etchant to spray-etch the copper foil 23a at the position where the resist is removed. Thereby, the wiring layer 23 is formed from the copper foil 23a. The formed wiring layer 23 is subjected to a blackening reduction process in order to improve adhesion with an insulating layer to be laminated thereafter. In addition, the thing of the state shown in FIG.2 (d) is referred later as the wiring board raw material 2 or 2a (2a which has the same structure).
[0038]
Next, as shown in FIG. 2E, a substantially conical conductive bump 43a is formed at a necessary position on the patterned wiring layer 23 (a position according to a specific wiring board layout). The conductive bumps 43a can be formed in the same manner as the conductive bumps 42a using, for example, a screen plate having 0.22 mm pits. The conductive paste formed by screen printing is dried and cured in an oven. The conductive bump 43 a can be positioned so as to overlap with the conductive bump 42 and the wiring layer 23.
[0039]
Next, using a dedicated machine, the prepreg (thickness is, for example, 0.06 mm) to be the insulating layer 13 is opposed to the insulating layer 12, and the conductive bumps 43a are semi-finished as shown in FIG. The cured prepreg is allowed to penetrate. As the prepreg, the same prepreg as in the case of the insulating layer 12 can be used. In addition, the thing of the state shown in FIG.2 (f) is referred later by the wiring board raw material 3. FIG.
[0040]
FIG. 3 shows a core wiring board (parts should be built in) using the wiring board material 3 shown in FIG. 2 (f) and the same structure 2a as the wiring board material 2 shown in FIG. 2 (d). 5 is a cross-sectional view or a partial plan view showing a manufacturing process up to the middle of forming a through hole for incorporating a component in the core wiring board.
[0041]
First, as shown in FIG. 3A, the wiring board material 3 and the wiring board material 2a are laminated and integrated, and the prepreg to be the insulating layer 13 is cured. The wiring board material 2a has the same configuration as that of the wiring board material 2 shown in FIG. 2 (d), and the conductive bumps 44 and the wiring layer 24 have predetermined positions or patterns (specific wiring boards). (Position or pattern according to the layout).
[0042]
For stacking and integration, for example, alignment is performed with a lay-up device, and the wiring board material 3 and the wiring board material 2a are stacked and set to a predetermined temperature and pressure profile using a vacuum laminating hot press. To do. As a result of the lamination and integration, the conductive bumps 43a are crushed and plastically deformed (= becomes conductive bumps 43), and electrical connection with the wiring layer 24 is established. Also, the wiring layer 24 sinks to the insulating layer 13 side due to the thermoplasticity (fluidity due to heat) of the prepreg to be the insulating layer 13.
[0043]
Thus, the core wiring board is formed. In this embodiment, the core wiring board having the four wiring layers (or copper foils) 22a, 23, 24, and 25a is formed as described above, but the number of wiring layers is not limited to four. For example, an even number of wiring layers such as 2, 6, 8,... Or an odd number of wiring layers such as 3, 5, 7,. In the case of the number of these wiring layers, it can be formed by applying the above-described process.
[0044]
For example, in the case of 6, the four-layer wiring board shown in FIG. 3A (which is formed by patterning a copper foil on one side) and the wiring board material 3 shown in FIG. Obtained by stacking and integrating. In the case of 3, the wiring board material 3 shown in FIG. 2 (f) is used instead of the wiring board material 1 shown in FIG. 2 (b), whereas FIG. 2 (c). It can be obtained by performing the process shown in FIG. Similarly, other layers can be obtained by appropriate combination.
[0045]
In this embodiment, the conductive bumps 42a, 43a, 44a that are interlayer-connected must be formed at a height penetrating the prepreg, and the formation height of the conductive bumps 42a, 43a, 44a is somewhat. Since there is a limit, the number of wiring layers of the core wiring board is preferably a number that takes into account the thickness of the components incorporated therein. In the case of the above description, the insulating layers 12, 13, and 14 are each 0.06 mm thick, and the total thickness is about 0.2 mm so that 0603 or 1005 size chip resistance can be accommodated. With the insulating layers 12, 13, and 14 having a thickness of 0.06 mm, sufficient penetration can be easily achieved with the formation height of the conductive bumps 42a, 43a, and 44a having a bottom diameter of about 150 μm or more. As a result, the number of wiring layers is four.
[0046]
However, if the formation height of the conductive bumps 42a, 43a, 44a is made higher, a thicker prepreg can be penetrated. As a result, even if the same component 33 is incorporated, the number of wiring layers of the core wiring board Can be reduced. Conversely, if the formation height of the conductive bumps 42a, 43a, 44a is lowered, a thinner prepreg is used, and as a result, the number of wiring layers of the core wiring board can be increased.
[0047]
Further, in this embodiment, the inter-layer connection of the core wiring board is configured by the conductive bumps 42, 43, and 44. However, the present invention is not limited to this. It may be due to a hall.
[0048]
Continuing the description of the process, when the core wiring board is formed, next, as shown in FIGS. 3B1 and 3B2, through holes 51 are formed at necessary positions of the core wiring board. The through-hole 51 is used to form a conductive layer in the thickness direction used for connection with the built-in component, and is a part of a space where the built-in component is located. Here, two through-holes 51 are provided for one built-in component so as to be adjacent to each other using a 0.4 mm diameter NC (numerical control) drill. After drilling the hole, the inside of the hole is cleaned by, for example, high-pressure water cleaning and desmear treatment using a predetermined chemical solution.
[0049]
Next, as shown in FIGS. 3C1 and 3C2, for example, a copper plating layer 52 is formed to a thickness of, for example, 20 μm so as to include the inner wall surface of the through hole 51. For the formation of the plating layer 52, for example, a continuous surface seed layer is first formed by electroless plating such as chemical copper plating, and then electrolysis is performed using, for example, a copper sulfate plating bath using the formed seed layer as a seed. This can be done by plating. The plating layer 52 can be efficiently formed by such two-stage plating. In addition, the plating layer 52 formed in the through hole 51 can be electrically connected to the wiring layers 23 and 24 in the middle of the core wiring board as illustrated.
[0050]
FIG. 4 is a cross-sectional view or a partial plan view showing the remaining manufacturing process for forming a through hole for incorporating a component in the core wiring board.
[0051]
After the plating layer 52 is formed as shown in FIGS. 3 (c1) and 3 (c2), next, the copper foils 22a and 25a on both sides (and the plating layer 52 located on both sides) are patterned to form the wiring layer 22. , 25 are formed. This patterning can be performed in the same manner as the step of forming the wiring layer 23 with reference to FIG. That is, the procedures are chemical polishing, resist dry film lamination, exposure through a photomask, development, and etching. The formed wiring layers 22 and 25 include land portions (the diameter thereof is, for example, 0.8 mm) with respect to the plating layer 52 formed on the inner wall surface of the through hole 51, as shown in FIG. 4 (a2). .
[0052]
Next, as shown in FIG. 4B, the core wiring board is formed so as to divide the plating layer 52 on the inner wall surface of the through hole 51 and to independently form the conductive layers 34 and 35 which are connection portions with the built-in components. Process. The processing method here depends on drilling using an NC drill. That is, two 0.8 mm-diameter plating layer dividing through holes 53 are formed almost adjacent to each other at a position on the core wiring board perpendicular to the direction in which the through holes 51 are arranged. According to the division of the plating layer 52 by such a drill, the conductive layers 34 and 35 can be easily divided and formed using an existing apparatus.
[0053]
Further, when the plating layer dividing through hole 53 is formed larger than the through hole 51 as shown in the drawing, when the component is not normally mounted in the subsequent component mounting step, the plating layer dividing through hole is formed. There is an advantage that 53 can function as a space for repair of component mounting.
[0054]
As described above, it is possible to obtain a core wiring board in which a space for incorporating a component (a space formed by the through hole 51 and the plating layer dividing through hole 53) is formed. Note that the plating layer 52 can be divided without using drilling. For example, there are a method of punching with a mold and a method using a cutting machine.
[0055]
FIG. 5 is a cross-sectional view or a partial plan view showing a component mounting process for incorporating components into the core wiring board. First, as shown in FIG. 5A, one side surface of the core wiring board is applied to the support member 61, and in this state, the component 33 is positioned at a predetermined position (a space for incorporation) by a mounting device such as a mounter. . Here, it is more preferable to provide the adhesive layer 61a on the surface of the support member 61. This is because the mounted component 33 is fixed to some extent by the adhesive layer 61a and can be used in the next process.
[0056]
Instead of the support member 61 having such an adhesive layer 61a, a heat-resistant adhesive tape (or a heat-resistant adhesive sheet) may be attached to one side of the core wiring board.
[0057]
Next, as shown in FIGS. 5B1 and 5B2, cream solders 36a and 37a (solder is, for example, Sn-3.0Ag-0.5Cu lead-free solder) at predetermined positions near both terminals of the component 33. Apply). Such application can be performed, for example, by screen printing or a dispenser. Here, screen printing using a screen plate having 0.5 mm diameter pits was used. The cream solders 36a and 37a may use conductive paste instead.
[0058]
FIG. 6 is a cross-sectional view showing a process of forming a component built-in wiring board as a finished product using the core wiring board on which the components are mounted. After the cream solders 36a and 37a are applied on the core wiring board as shown in FIGS. 5 (b1) and 5 (b2), the cream solders 36a and 37a are then reflowed in a reflow furnace. As a result, the state shown in FIG. 6A is obtained, and the solders 36 and 37 as connection members establish electrical and mechanical connections between the conductive layers 34 and 35 and the terminals of the component 33. In the case where a conductive paste is used instead of the cream solders 36a and 37a, this is dried and cured, for example, in an oven to establish an electrical / mechanical connection.
[0059]
The component-mounted core wiring board 4 obtained as described above is subjected to blackening reduction treatment in order to improve the adhesion between the wiring layers 22 and 25 on both surfaces thereof and the insulating layer to be laminated thereafter.
[0060]
Next, as shown in FIG. 6B, wiring board materials 1a and 1b are laminated on both sides of the core wiring board 4, and these are integrated. At this time, the prepreg to be the insulating layers 11 and 15 is cured. The wiring board materials 1a and 1b have the same configuration as that of the wiring board material 1 shown in FIG. 2B, and the conductive bumps 41 or 45 are in a predetermined position (according to a specific wiring board layout). Position).
[0061]
For this lamination / integration, for example, alignment is performed using a lay-up device, and the core wiring board 4 and the wiring board materials 1a and 1b are arranged so as to overlap each other. Set in the profile. As a result of this lamination and integration, the conductive bumps 41 and 45 are plastically deformed by crushing their heads, and electrical connection with the wiring layer 22 or 25 is established.
[0062]
Further, the wiring layer 22 is positioned by sinking to the insulating layer 11 side due to the thermoplasticity (fluidity due to heat) of the prepreg to be the insulating layer 11, and the wiring layer 25 is thermoplasticity of the prepreg to be the insulating layer 15. Due to (fluidity due to heat), it sinks to the insulating layer 15 side and comes to a position. Further, due to the thermoplasticity (fluidity due to heat) of the prepreg to be the insulating layers 11 and 15, the insulating layer is also integrally formed with the insulating layers 11 and 15 in the periphery so as to cover and closely adhere the built-in component 33. It is formed. This eliminates the need for a hole filling process around the part 33, which simplifies the process and prevents the generation of voids, thereby improving the reliability.
[0063]
Note that the wiring board material laminated on the outside may be one having a larger number of wiring layers instead of the one shown in FIG. For example, one having two wiring layers shown in FIG. 2 (f), and similarly having three or more wiring layers may be used. Moreover, the wiring board material laminated | stacked on the outer side does not necessarily need to be accompanied by the conductive bump 42a as shown in FIG.2 (b). In this case, since there is no conductive bump 42a, the interlayer connection between the copper foil 21a (26a) and the wiring layer 22 (25) cannot be made by the conductive bump, but a through hole is provided in the laminated wiring board. These interlayer connections can be made by lever holes.
[0064]
After the insulating layer to be positioned outside is laminated and integrated with the core wiring board, next, as shown in FIG. 6 (c), patterning is performed on the copper foils 21a and 25a on both outer sides, and the wiring layer 21, 26 is formed. This patterning can be performed in the same manner as the step of forming the wiring layer 23 with reference to FIG. That is, the procedures are chemical polishing, resist dry film lamination, exposure through a photomask, development, and etching. In addition, after the formation of the outer insulating layers 11 and 15 described above, an insulating layer may be further laminated and integrated (build-up) in the same manner on the outer side.
[0065]
Next, as shown in FIG. 6C, solder resists 31 and 32 are formed at predetermined positions on the outermost surface. Further, a nickel / gold (nickel base) layer (not shown) is formed by electroless plating at a portion of the wiring layer 21 or 26 where the solder resist is not formed to prevent corrosion. And a wiring board is cut out so that it may become a predetermined | prescribed external shape with a router processing machine. Thus, the component built-in wiring board according to the present embodiment can be obtained.
[0066]
In this embodiment, the existing manufacturing equipment can be used almost as it is, which leads to a reduction in the manufacturing cost of the wiring board. In addition, since the conductive bumps 41 to 45 that can be arranged at overlapping positions are used for the interlayer connection, the wiring length can be shortened to improve the efficiency and electrical characteristics, thereby laying out the wiring board. In particular, since chip resistors and chip capacitors having a relatively large number of mounting points can be incorporated, the current design rules can be relaxed and higher-density mounting can be achieved.
[0067]
【The invention's effect】
As described above in detail, according to the present invention, the conductive layer for connecting to the terminal of the built-in component is formed in the plate thickness direction. Therefore, the connection between the terminal of the component and the conductive layer is horizontal, for example. It is made by a conductive member having a shape bridged in the direction. Therefore, the gap is less likely to occur around the built-in component, and the upper and lower two insulating layers can be in close contact with the built-in component. Therefore, no gap is generated around the built-in component, and reliability is not deteriorated.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view and a partial plan view schematically showing the structure of a component built-in wiring board according to an embodiment of the present invention.
FIG. 2 is a schematic cross-sectional view showing a process for manufacturing a component built-in wiring board according to an embodiment of the present invention.
FIG. 3 is a continuation diagram of FIG. 2 and schematically showing a process of manufacturing a component built-in wiring board according to an embodiment of the present invention in a cross-section or a partial plane.
FIG. 4 is a continuation diagram of FIG. 3 and schematically showing a process of manufacturing a component built-in wiring board according to an embodiment of the present invention in a cross-section or a partial plane.
FIG. 5 is a continuation diagram of FIG. 4 and schematically showing a process of manufacturing a component built-in wiring board according to an embodiment of the present invention in a cross-section or a partial plane.
6 is a continuation diagram of FIG. 5 and schematically showing a process of manufacturing a component built-in wiring board according to an embodiment of the present invention in cross section.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1, 1a, 1b ... Wiring board material 2, 2a ... Wiring board material 3 ... Wiring board material 4 ... Wiring board material (core wiring board) 11, 12, 13, 14, 15 ... Insulating layer 21, 22, 23, 24 , 25, 26 ... wiring layers 21a, 22a, 23a, 25a, 26a ... copper foil 31, 32 ... solder resist 33 ... electrical / electronic components 34, 35 ... conductive layers 36, 37 ... solder 36a, 37a ... cream solder 41, 42, 43, 44, 45 ... conductive bump (after connection formation) 42a, 43a ... conductive bump (before connection formation) 51 ... through hole 52 ... plating layer 53 ... plating layer split through hole 61 ... support member 61a ... adhesive layer

Claims (10)

A wiring board with built-in components,
A first arc of a first radius, a second arc of a second radius greater than the first radius that is continuous with the first arc, and a third of the first radius that is substantially continuous with the second arc. and arcs, and the first insulating layer formed of an opening having a substantially the fourth edge arc Ru is composed of a second radius continuing the arc and the first arc of the third,
To each of the first arc and the third circular arc of the inner wall surface on the edge of the opening, formed substantially perpendicularly to the plate in the direction of the component built-in wiring board, and of the component built-in wiring board First and second conductive layers embedded in the upper and lower surfaces without being exposed;
First, a second terminal, the first is the embedded, said each second conductive layer first, second terminal is embedded in the plate of the component built-in wiring board so as to face An electric / electronic component having a shape that is substantially plane-symmetric in the thickness direction;
Wherein said first buried electrical / electronic components, wherein the second terminal first, the provided gap between the second conductive layer first, the second terminal first, second First and second solders for electrically and mechanically connecting the conductive layers, respectively ;
The outer surface of the embedded electric / electronic component is provided so as to cover the portion other than the portion connected to the first and second solders and to be in close contact with the electric / electronic component in the vertical direction of the plate thickness. and wherein the first, second said conductive layer the wiring board the first order to buried in the plates, the upper and lower end surfaces of the second conductive layer provided so as to sandwich from above and below the upper and lower two second A component built-in wiring board, comprising: a third insulating layer.   2. The component built-in wiring board according to claim 1, wherein the electric / electronic component is a chip capacitor, a chip resistor, or a chip inductor. 2. The component built-in wiring board according to claim 1, wherein the first and second conductive layers further include a wiring layer capable of being electrically connected in the lateral direction, and the number thereof is four.   4. The component built-in wiring board according to claim 3, wherein the wiring layers are electrically connected to each other by conductive bumps.   The component built-in wiring board according to claim 4, wherein the conductive bump is positioned so as to overlap the wiring layer. Two inner wiring layers provided in contact with the inner surfaces of the upper and lower two second and third insulating layers,
Two outer wiring layers provided in contact with the outer surfaces of the upper and lower two second and third insulating layers, respectively.
2. The component built-in wiring according to claim 1, wherein the inner wiring layer and the outer wiring layer sandwiching the upper and lower two second and third insulating layers are electrically connected by conductive bumps. Board. Producing a core wiring board having a first conductive layer on at least both upper and lower surfaces;
Forming two through holes that are substantially perpendicular to the in-plane direction and adjacent to the circular hole in the manufactured core wiring board; and
Forming a second conductive layer on the inner wall surface of the two through holes formed;
Patterning the first conductive layer;
The two through holes Ri Do the single through-hole with four arcs, and the two said to be formed on the inner wall surface on the through-hole the second conductive layer is the third, the fourth conductive layer to so that is divided at a position of the second conductive layer the core wiring board facing perpendicular to a direction in which the two through holes of the formed core wiring board are aligned in the radius having the two through holes respectively Drilling at two locations with a larger radius ;
In the single through-hole, the first and second terminals face each of the third and fourth conductive layers formed by dividing the second conductive layer by the drilling. Positioning an electrical / electronic component having a substantially plane-symmetric shape in the thickness direction;
Connecting the first and second terminals of the positioned electrical / electronic component and the third and fourth conductive layers with solder;
The upper and lower end surfaces of the divided conductive layer are overlapped on both upper and lower surfaces of the core wiring board to which the electric / electronic component is connected by the solder, and the periphery of the electric / electronic component is approximately in the plate thickness direction. And a step of laminating and forming insulating layers so as to be filled symmetrically.   The step of manufacturing the core wiring board having the first conductive layers on at least the upper and lower surfaces is for manufacturing a core wiring board having four wiring layers, and the electrical connection between these wiring layers is conductive. 8. The method of manufacturing a component built-in wiring board according to claim 7, wherein the wiring board is manufactured so as to be made of a conductive bump.   The step of forming the second conductive layer on the inner wall surface of the two through-holes formed includes the step of forming a conductive layer as a base by electroless plating, and using the formed base as a seed. The method of manufacturing a component built-in wiring board according to claim 7, further comprising a step of forming an upper conductive layer by electrolytic plating. A substantially plane-symmetrical shape in the thickness direction in the single through hole so that the first and second terminals face each of the third and fourth conductive layers formed by the drilling. The step of locating the electric / electronic component comprising: a supporting member placed under the core wiring board excluding the single through hole, and the electric / electronic component being positioned on the supporting member. The method of manufacturing a component built-in wiring board according to claim 7.

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